Immunodetection of myeloid and plasmacytoid dendritic cells in mammary carcinomas of female dogs / Imunodetecção de células dendríticas mieloides e plasmocitoides nos carcinomas mamários em cadelas

Dendritic cells have attracted great interest from researchers as they may be used as targets of tumor immune evasion mechanisms. The main objective of this study was to evaluate the relationship between the dendritic cells (DCs) subpopulation in simple type mammary carcinomas in female dogs. Two groups of samples were used: the control group consisted of 18 samples of mammary tissue without changes and the tumor group with 26 simple type mammary carcinomas. In these groups, we evaluated the immunodetection of immature and mature myeloid DCs, plasmacytoid DCs and MHC-II. In mammary tumor, mature myeloid DCs predominated in the peritumoral region, while immature myeloid DCs and plasmacytoid DCs were evident in the intratumoral region. Immunostaining of MHC-II was visualized in mammary acini (control group), in tumor cells and inflammatory infiltration associated with tumors. The comparison between the control and tumor groups showed a statistically significant difference between immature myeloid DCs, mature myeloid DCs and plasmacytoid DCs. The immunodetection of MHC-II was not significant when comparing the groups. The predominance of immature DCs in the tumor group is possibly related to an inefficient immune response, promoting the development and survival of tumor cells. The presence of plasmacytoid DCs in the same group suggests a worse prognosis for female dogs with mammary tumors. Therefore, the ability of differentiation of canine dendritic cells could be influenced by neoplastic cells and by the tumor microenvironment...

As células dendríticas têm despertado grande interesse dos pesquisadores, pois podem ser alvo dos mecanismos de evasão imune do tumor. O objetivo principal deste estudo foi avaliar a relação entre as subpopulações de células dendríticas (DCs) nos carcinomas mamários do tipo simples em cadelas. Dois grupos de amostras foram utilizados, o grupo controle composto por 18 amostras de tecido mamário sem alterações e o grupo tumor com 26 carcinomas mamários do tipo simples. Nestes grupos foram avaliadas a imunodetecção de DCs mieloides imaturas e maduras, DCs plasmocitoides e de MHC-II. Nas mamas com tumor, as DCs mieloides maduras predominaram na região peritumoral, enquanto que as DCs mieloides imaturas e as DCs plasmocitoides foram evidentes na região intratumoral. A imunomarcação do MHC-II foi visualizada nos ácinos mamários (grupo controle), nas células tumorais e no infiltrado inflamatório associado aos tumores. Na comparação entre os grupos controle e tumor houve diferença estatística significativa entre as DCs mieloides imaturas, DCs mieloides maduras e DCs plasmocitoides. A imunodetecção de MHC-II não foi significativa na comparação entre os grupos. A predominância de DCs imaturas no grupo tumor, possivelmente, está relacionada com uma resposta imune ineficiente, favorecendo o desenvolvimento e a sobrevivência das células tumorais. A presença das DCs plasmocitoides no mesmo grupo sugere um prognóstico pior para cadelas com tumores de mama. Portanto, a capacidade de diferenciação das células dendríticas caninas poderia ser influenciada pelas células neoplásicas e pelo microambiente tumoral...

Efectores celulares de la respuesta inflamatoria en la enfermedad pulmonar obstructiva crónica / Cellular effectors of the inflammatory response in chronic obstructive pulmonary disease (COPD)

Approximately 3 million people in the world die every year as a consequence of COPD, which is associated with an abnormal inflammatory response of the lung to noxious particles and gases. This inflammatory pattern causes pathological changes leading to a narrowing of small airways and destruction of lung parenchyma, also known as emphysema. Classically, these changes were associated to macrophages and neutrophils, although T CD8+ lymphocytes were latter added to the equation to explain the origin of emphysematous lesions. However, in recent years, multiple evidences have arisen indicating that inflammatory response in COPD is much more complex. These findings point to a key role for mast cells, dendritic cells, T CD4+ and B cells. The aim of this article is to review such evidence and report what is known so far about those cells involved in the inflammatory response in COPD.

Efecto de la Leishmania mexicana, RANTES y TNF alfa en el fenotipo y propiedades migratorias in vitro de células dendríticas esplénicas de ratones BALB/c neonatos y adultos / Dendritic cells of BALB/c mice: phenotypic characteristics and migratory properties

Las células dendríticas (CDs) son esenciales en el desarrollo y regulación la respuesta inmunitaria (RI). Existen controversias en cuanto al potencial de inducción de la RI por las CDs en el período neonatal. Se ha propuesto que la RI específica de un neonato depende de la relación cuantitativa CD/linfocito T, y del momento, etapa neonatal o adulta, del encuentro con el antígeno, lo que parece influir sobre las propiedades fenotípicas y biológicas de las CDs, modificando su comportamiento. Por tal motivo, nos planteamos evaluar el efecto de un antígeno, Leishmania mexicana (L. mexicana) y de las citoquinas TNFa y RANTES sobre las características fenotípicas y propiedades migratorias, in vitro, de las CDs esplénicas provenientes de ratones BALB/c neonatos y adultos, usando citometría de flujo y la cámara de Boyden. Las CDs de ratones neonatos y adultos, en condiciones basales, expresan de manera similar, las moléculas CD40, CD86, CMHII y CD54. Este mismo fenómeno se observó al incubar dichas células con el Ag (L. mexicana) a excepción de la molécula CD40 cuya intensidad de expresión se elevó significativamente (P<0,05) en ambos grupos de estudio. El índice de migración de las CDs en presencia de medio de cultivo condicionado de L. mexicana, RANTES y TNFa fue mayor en adultos que en neonatos. Estos resultados muestran que las CDs neonatales son fenotípicamente similares a las adultas. Ante los mismos estímulos se comportan de manera diferente, sugiriendo la existencia de otros factores, que pudieran explicar la mayor susceptibilidad a infecciones en la etapa neonatal.

Dendritic cells (DCs) are essential in the development and regulation of the immune response (IR). The inherent potential of DCs to induce a specific immune response in the neonatal period is controversial. It has been suggested that the specific IR in neonates depends on the quantitative relation of DC/T lymphocytes, as well as on the neonatal or adult age at which the interaction antigen/DC/T lymphocytes occurs. This suggests that this contact has an influence on the phenotypic and/or biological properties of DCs, which modifies its behavior. Therefore, the effects of Leishmania mexicana (L. mexicana) and of TNFa and RANTES cytokines on immunophenotypical characteristics were evaluated on spleen DCs, from neonate and adult BALB/c mice, by using flow cytometry and in vitro migratory properties with a Boyden Chamber. In basal conditions, neonate and adult DCs express the same molecules (CD40, CD86, MHCII and CD54). When the DCs interact with the antigen L. mexicana, the expression of these molecules are similar in adults and in neonates, with the exception of CD40 whose intensity of expression was raised (P<0,05) in both groups. The rate of migration of the DCs in a culture medium conditioned of L. mexicana, RANTES and TNFa was higher in adults than in newborn mice. These observations suggest that neonatal and adult mice DCs have similar phenotypic characteristics. Under the effect of the same stimulus they respond differently; suggesting that other factors are involved in the higher susceptibility that newborns have to infections.

Leucemia de células dendríticas: a propósito de un caso / Dendritic leukemia cells: a purpose of a case

La leucemia de células dendríticas son patologías poco frecuentes, que involucran fundamentalmente a la piel, pero con una alta tendencia de metástasis. La inmunohistoquímica es una herramienta valiosa junto con la biopsia para el diagnóstico definitivo. Se presenta el caso de una paciente joven, quien acudió por presentar una lesión en la pierna izquierda de dimensiones y características únicas, cuyo diagnóstico requirió de la utilización de marcadores monoclonales específicos en la identificación de esta entidad.

The dendritic cell leukemias are pathologies very uncommon which involve mainly the skin, but with a high tendency of metastasis. The flow cytometric is a valuable tool together with tissue biopsy for a definitive diagnosis. We present the case of a young female who complained for a left leg lesion with unique dimensions and characteristics, in where the diagnostic process required the use of the specific monoclonal markers in the identification of this particular disease.

Functional changes of dendritic cells in hypersensivity reactions to amoxicillin

A better understanding of dendritic cell (DC) involvement in responses to haptenic drugs is needed, because it represents a possible approach to the development of an in vitro test, which could identify patients prone to drug allergies. There are two main DC subsets: plasmacytoid DC (pDC) and myeloid DC (mDC). β-lactams form hapten-carrier conjugates and may provide a suitable model to study DC behavior in drug allergy reactions. It has been demonstrated that drugs interact differently with DC in drug allergic and non-allergic patients, but there are no studies regarding these subsets. Our aim was to assess the functional changes of mDC and pDC harvested from an amoxicillin-hypersensitive 32-year-old woman who experienced a severe maculopapular exanthema as reflected in interleukin-6 (IL-6) production after stimulation with this drug and penicillin. We also aim to demonstrate, for the first time, the feasibility of this method for dendritic cell isolation followed by in vitro stimulation for studies of drug allergy physiopathology. DC were harvested using a double Percoll density gradient, which generates a basophil-depleted cell (BDC) suspension. Further, pDC were isolated by blood DC antigen 4-positive magnetic selection and gravity filtration through magnetized columns. After stimulation with amoxicillin, penicillin and positive and negative controls, IL-6 production was measured by ELISA. A positive dose-response curve for IL-6 after stimulation with amoxicillin and penicillin was observed for pDC, but not for mDC or BDC suspension. These preliminary results demonstrate the feasibility of this methodology to expand the knowledge of the effect of dendritic cell activation by drug allergens.

Effect of aging and oral tolerance on dendritic cell function

Oral tolerance can be induced in some mouse strains by gavage or spontaneous ingestion of dietary antigens. In the present study, we determined the influence of aging and oral tolerance on the secretion of co-stimulatory molecules by dendritic cells (DC), and on the ability of DC to induce proliferation and cytokine secretion by naive T cells from BALB/c and OVA transgenic (DO11.10) mice. We observed that oral tolerance could be induced in BALB/c mice (N = 5 in each group) of all ages (8, 20, 40, 60, and 80 weeks old), although a decline in specific antibody levels was observed in the sera of both tolerized and immunized mice with advancing age (40 to 80 weeks old). DC obtained from young, adult and middle-aged (8, 20, and 40 weeks old) tolerized mice were less efficient (65, 17 and 20 percent, respectively) than DC from immunized mice (P < 0.05) in inducing antigen-specific proliferation of naive T cells from both BALB/c and DO11.10 young mice, or in stimulating IFN-g, IL-4 and IL-10 production. However, TGF-â levels were significantly elevated in co-cultures carried out with DC from tolerant mice (P < 0.05). DC from both immunized and tolerized old and very old (60 and 80 weeks old) mice were equally ineffective in inducing T cell proliferation and cytokine production (P < 0.05). A marked reduction in CD86+ marker expression was observed in DC isolated from both old and tolerized mice (75 and 50 percent, respectively). The results indicate that the aging process does not interfere with the establishment of oral tolerance in BALB/c mice, but reduces DC functions, probably due to the decline of the expression of the CD86 surface marker.

Mycobacterium leprae interactions with the host cell: recent advances.

The significance of Hansen disease, or leprosy, is underscored by fact that detection of this disease has remained stable over the past 10 yr, even though disease prevalence is reduced. Due to the long incubation time of the organism, health experts predict that leprosy will be with us for decades to come. Despite the fact that Mycobacterium leprae, the causative agent of leprosy, cannot be cultured in the laboratory, researchers are using innovative and imaginative techniques to discern the interactions of M. leprae with host cells both in vitro and in vivo to identify the host and bacterial factors integral to establishment of disease. The studies described in this review present a new and evolving picture of the many interactions between M. leprae and the host. Specific attention will be given to interactions of M. leprae bacilli with host Schwann cells, macrophages, dendritic cells and endothelial cells. The findings described also have implications for the prevention and treatment of leprosy.

Mecanismo de presentación antigénica en el tejido pulpar / Mechanism of antigenic presentation in the pulp tissue

La infección multimicrobiana de la pulpa dental desencadena respuetas inflamatorias. Bacterias y sustancias nocivas pueden alcanzar acceso directo a la pulpa por medio de los túbulos dentinarios. En años recientes, la investigación en biología pulpar ha brindado profundo entendimiento de los mecanismos básicos que gobiernan la defensa y reparación pulpar. Células dendríticas (células profesionales presentadoras de antígeno) son tanto sensoras como mensajeras que forman una red de advertencia inicial de diferentes tejidos y expresan antígenos Clase II que indican la capacidad para presentar antígenos a células T helper. Estas células están localizadas en la capa odontoblástica, así como en la porción central del tejido pulpar y juegan un papel importante en la captura de antígenos, migración al nódulo linfático regional. Sin embargo, la presencia de células T en tejido pulpar normal demuestra que éste es provisto con células inmunocompetentes esenciales para la iniciación de la respuesta inmune. Las células dendríticas pueden interactual también con vasos y nervios pulpares. De este modo la respueta neuroinmunológica de la pulpa puede ser la primera reacción de defensa en el órgano dentinopulpar

Células dendríticas: origem, distribuição, morfologia, estrutura, atividade funcional e métodos de identificação - uma revisão / Dendritic cells: origin, distribuition, morphology, structure, fuctional activity and identifity methods - a review

As células dendríticas desempenham um importante papel na resposta imunológica, atuando como uma verdadeira célula apresentadora de antígeno. O presente trabalho compreende uma extensa revisão da literatura acerca dos principais aspectos referentes à embriologia, citologia e histofisiologia das referidas células, abordando ainda, de forma sucinta, os relevantes métodos utilizados para a identificação das mesmas

Involvement of tumor necrosis factor receptor superfamily (TNFRSF) members in the pathogenesis of inflammatory diseases

Current therapies for autoimmune diseases are not cures but merely palliatives, aimed at reducing symptoms. For the most part, these treatments provide nonspecific suppression of the immune system and thus do not distinguish between a pathogenic autoimmune response and a protective immune response. Recently emerging evidence not only has indicated the involvement of members of the TNF receptor/ligand superfamilies but also has revealed exciting innovative strategies for the treatment of autoimmune diseases and other chronic inflammatory diseases without depressing the immune response in general. In this review, we will discuss the regulatory mechanisms of TNF receptor/ligand family members, such as HVEM/ LIGHT, 4-1BB/4-1BBL, and GITR/GITRL that regulate T and B cell functions and participate in the process of inflammatory diseases. We will also discuss how intervening in the costimulatory pathways mediated by these molecules might have some potential as a therapeutic approach to immune disorders.

The low efficiency of dendritic cells and macrophages from mice susceptible to Paracoccidioides brasiliensis in inducing a Th1 response

In the present study we evaluated T cell proliferation and Th lymphokine patterns in response to gp43 from Paracoccidioides brasiliensis presented by isolated dendritic cells from susceptible and resistant mice. T cell proliferation assays showed that dendritic cells from susceptible mice were less efficient than those from resistant mice. The pattern of T cell lymphokines stimulated by dendritic cells was always Th1, although the levels of IL-2 and IFN-gamma were lower in T cell cultures from susceptible mice. To determie whether different antigen-presenting cells such as macrophages and dendritic cells stimulated different concentrations of Th1 lymphokines, the production of IFN-gamma and IL-2 was measured. It was observed that dendritic cells were more efficient than macrophages in stimulating lymphoproliferation in resistant mice. However, no significant difference was observed for IFN-gamma or IL-2 production. When cells from susceptible mice were used, macrophages were more efficient in stimulating lymphoproliferation than dendritic cells, but no difference was observed in the production of Th1 cytokine. Taken together, these results suggest the lower efficiency of dendritic cells and macrophages from B10.A mice in stimulating T cells that secrete Th1 lymphokines in vitro, an effect that may be involved in the progression of the disease in vivo

Cancer immunotherapy using dendritic cell-derived exosomes

Dendritic cells (DCs) are the most potent antigen presenting cells and the only ones capable of inducing primary cytotoxic immune responses. We found that DCs secrete a population of membrane vesicles, called exosomes. Exosomes are 60-80 nm vesicles of endocytic origin. The protein composition of exosomes was subjected to a systematic proteomic analysis. Besides MHC and co-stimulatory molecules, exosomes bear several adhesion proteins, most likely involved in their specific subjected to targeting. We also found that exosomes accumulate several cytosolic factors, probably involved in their endosomal biogenesis. Like DCs, exosomes induced immune responses in vivo. Indeed, a single injection of DC-derived exosomes sensitized with tumor peptides induced potent anti tumor immune responses in mice and the eradication of established tumors. Tumor-specific cytotoxic T lymphocytes were found in the spleen of exosome-treated mice, and the anti tumor effect of exosomes was sensitive to in vivo depletion of CD8+ T cells. These results show that exosomes induce potent anti tumor effects in vivo, and strongly support the implementation of human DC-derived exosomes for cancer immunotherapy.

Las células dendríticas: posible aplicaciones terapéuticas / The dendritic cells: terapeutics applications possible

La interación entre el sistema inmune y las células tumorales o microorganismos es muy complejas, involucra una serie de tipos celulares y mediadores. Las células dentríticas juegan un papel fundamental en el desarrollo del sistema inmune, son las células presentadoras de antígeno profesionales más importantes en la activación de células T en reposo y de linfocitos T vírgenes. Estas características señalan a las células dentríticas como fundamentales para una respuesta inmune efectiva. Actualmente, esta células son el blanco para las vacunas génicas, con el objetivo de utilizarlas en inmunoterapia y para el desarrollo de vacunas

Celulas dendriticas y su papel en patologia / Dendritic cells: their role in pathology

La finalidad de esta revisión es aportar un conocimiento general sobre las células dendríticas (CD), células accesorias de la respuesta inmune. Se las reconoce como las células presentadoras de antígenos por excelencia (APC) y por lo tanto expresan antígenos clase II del complejo mayor de histocompatibilidad (MHC). Los diversos tipos de CD tienen un origen común en la médula ósea diferenciándose luego bajo la influencia de variados estímulos y distribuyéndose en órganos linfoideos y no linfoideos. Desde los tejidos periféricos migran a los ganglios linfáticos donde presentan el antígeno a los linfocitos T. Dependiendo del microambiente expresan diversos marcadores de superfície siendo capaces de la secreción de citoquinas como IL-12, IL-1 y TNFalpha. Como APC cumplen un importante papel en la patogenia de enfermedades autoinmunes y virales destacándose su participación en la infección por HIV. Se las encuentran en el infiltrado de numerosos cánceres humanos donde actuando como APC podrían incluir una respuesta inmune antitumoral. En esta propiedad se basa su utilización para el tratamiento de linfomas y melanomas llevada a cabo actualmente en diversos laboratorios.

Ex vivo generation of functional dendritic cells from mobilized CD34+ hematopoietic stem cells

The ability to generate dendritic cells (DCs) in sizeable numbers has enormous implications for the development of clinically-effective antigen presentation procedures for cancer immunotherapy. We evaluated the generation of immunostimulatory DCs from peripheral blood CD34+ cells collected from healthy donors. CD34+ cells purified from leukapheresis product were seeded at 1 x 10(4) cells/mL in complete medium supplemented with GM-CSF, TNF alpha, IL-4, c-kit ligand, and flt3 ligand (FL). By day 14 of culture in the presence of GM-CSF + TNF alpha, the total cell number increased by 23.4 +/- 5.4-fold compared to the starting number of CD34+ cells. When the c-kit and FL were added to GM-CSF and TNF alpha, the cell number increased by 109.8 +/- 11.2-fold without affecting the immunophenotype of recovered cells. Flow cytometric analysis indicated that cells with the markers of mature dendritic cells, i.e., CD1a +CD14 -HLA-DR+, and CD80+CD86+HLA-DR+, constituted 49.0% +/- 7.5%, and 38.9% +/- 6.5%, respectively. This pattern of expression of surface antigen was unchanged whether the c-kit ligand and/or FL was added. The irradiated CD1a+HLA-DR+ cells recovered from in vitro cultures elicit a vigorous proliferation of allogeneic peripheral blood T-cells, irrespective of cytokine combinations. These findings provide advantageous tools for the large-scale generation of DCs that are potentially usable for clinical protocols of immunotherapy or vaccination in patients undergoing cancer treatment.

Identificacion de un antigeno tumoral asociado al receptor estrogenico en ganglios linfaticos axilares de pacientes con cancer mamario / Identification of a tumor antigen associated to the estrogen receptor in axillary lymph nodes of breast cancer patients

Dieciseis ganglios linfáticos axilares fueron enfrentados con suero de pacientes portadoras de cáncer mamario, encontrándose que dichos sueros reconocían determinantes antigénicos en células foliculares dendríticas (CFD) de los centros germinativos. Este hecho fue corroborado con CFD aisladas y cultivadas a las que se enfretó con los sueros experimentales. Con sueros normales, los resultados fueron negativos. Posteriormente sobre los mismos ganglios y las CFD aisladas, se realizó técnica de inmunoperoxidasa con anticuerpos monoclonales anti-proteína asociada al receptor estrogénico (ERAP). En el 75 por ciento de los casos, los ganglios mostraron células anti-ERAP+ en el seno subcapsular, sinusoides corticales y centros germinativos. El fenotipo de las células correspondió a macrófagos y células foliculares dentríticas respectivamente. Controles utilizando ganglios que drenan otros tumores malignos fueron negativos. Estoshallazgos sugieren que el antígeno tumoral podría corresponder a la proteína asociada al receptor de estrógenos o tal vez al mismo receptor, capaz de ser captado y transportado por células presentadoras de antígenos desde el tumor a los ganglios linfáticos regionales donde se produce la respuesta inmune del huésped. El posible reconocimiento de un antígeno tumoral mamario abre una perspectiva futura para el manipuleo terapéutico de esta enfermedad.